Lewis acid activation of Weiss' reagents ([PhI(Pyr)2]²⁺) with boranes and isolation of [PhI(4-DMAP)]²⁺

<p dir="ltr">Abstraction of a pyridine ligand from Weiss' reagent ([PhI(Pyr)2]²⁺) using BF₃-Et₂O was found to activate Weiss' reagent towards electrophilic aromatic substitution reactions. The activated species can be isolated when 4-DMAP is used as the pyridine ligand and was determined to be [PhI(4-DMAP)]²⁺ in solution. The isolated cation was reactive in electrophilic aromatic substitution reactions towards mesitylene, xylene and toluene that Weiss' reagent itself does not react with.</p>